Anthracenyl Groups Research Articles

Ferrocenyl chalcones containing anthracenyl group: Synthesis, X-ray crystal structures and electrochemical properties

Two ferrocenyl chalcones containing the anthracenyl group, Fc–COCH CH–Anth (Fc–Anth) and Anth–COCH CH–Fc (Anth–Fc), were prepared by solvent-free aldol condensation using acetylferrocene/9-anthraldehyde and 9-acetylanthracene/ferrocenecarboxaldehyde, respectively. The X-ray crystal structure analyses showed that these products crystallize as racemic mixtures. High torsion angles between the anthracenyl group and the enone linkage were observed for Fc–Anth (55.7(4)°) and Anth–Fc (74.9(4)°) and the enone linkage has different conformations for Fc–Anth (s- cis) and Anth–Fc (s- trans). The cyclic and differential pulse voltammetry analyses showed one reversible cycle corresponding to the Fc/Fc + process ( E 1/2 = 0.402 V for Fc–Anth and 0.277 V for Anth–Fc), and one irreversible peak corresponding to the oxidation of the anthracenyl group ( E pa 2 = 1.073 V for Fc–Anth and 1.153 V for Anth–Fc). The fluorescence properties of the anthracenyl group were quenched in these chalcones, possibly by the ferrocenyl group.

Pyrazolyl–Diamine Ligands That Bear Anthracenyl Moieties and Their Rhenium(I) Tricarbonyl Complexes: Synthesis, Characterisation and DNA‐Binding Properties

Two novel families of pyrazolyl-diamine ligands that bear an anthracen-9-yl group as a DNA-binding fragment, pz*(CH2)2NH(CH2)2NHCH2-9-anthryl (pz*=pz (L(1)), 3,5-Me2pz (L2)) and pz*(CH2)2NH(CH2)2NH(2 (pz*=4-(9-anthrylmethyl)pz (L3), 3,5-Me2-4-(9-anthrylmethyl)pz (L4)), have been prepared and fully characterised. In the case of L2-L4, the evaluation of their coordination capability towards the fac-[Re(CO)3]+ core led to the synthesis of the organometallic complexes fac-[Re(CO)(3){3,5-Me(2)pz(CH2)2NH(CH2)2NHCH2-9-anthryl}]Br (7) and fac-[Re(CO)3{4-(9-anthrylmethyl)pz*(CH2)2NH(CH2)2NH2}]Br (pz*=pz (8), 3,5-Me2pz 9). The interaction of the novel pyrazole-diamine ligands and the rhenium(I) complexes with calf thymus (CT) DNA has been investigated with a variety of spectroscopic techniques (UV-visible, fluorescence, circular dichroism (CD) and linear dichroism (LD)). All of the evaluated compounds have a moderate affinity to CT DNA (3.46x10(3)<K(b)<1.95x10(4)), but the binding mode depends on the position of the chromophore in the framework of the pyrazolyl-diamine ligands. LD measurements have shown that L1 and L2 act as DNA intercalators, but complex 7 intercalates only partially. By contrast, the compounds with the anthracenyl group at the 4-position of the azolyl ring (L(3), L4 and 9) do not intercalate, and behave more like DNA groove binders. Fluorescence microscopy studies have demonstrated that complexes 7 and 9 can target the nucleus of murine B16-F1 melanoma cells, and appear to be promising platforms for the further design of radiopharmaceuticals for targeted radiotherapy.

Synthesis of ω‐functionalized poly(1,3‐cyclohexadiene): addition of fluorescent functional group to the polymer chain end

AbstractBACKGROUND: Poly(1,3‐cyclohexadiene) (PCHD) is of interest as a precursor for the synthesis of a new class of high‐performance hydrocarbon polymers. ω‐Functionalization of PCHD offers a new opportunity for the preparation of a variety of multifunctional PCHD derivatives.RESULTS: ω‐Functionalized PCHD containing a fluorenyl (or anthracenyl) group at the polymer chain end was successfully synthesized by post‐polymerization reaction of poly(1,3‐cyclohexadienyl)lithium (PCHDLi) with alkyl halides containing a fluorescent functional group. The degree of nucleophilicity of PCHDLi and the control of side reactions were very important factors to achieve a high conversion for the post‐polymerization reactions of PCHDLi. The ω‐functionalized PCHDs obtained exhibited strong photoluminescence and the wavelength of the fluorescence was adjustable by changing the structure of the ω‐functional group.CONCLUSION: ω‐Functionalized PCHD is a preferable precursor that can be utilized to obtain a new class of multifunctional hydrocarbon polymers containing six‐membered rings in the main chain. Copyright © 2007 Society of Chemical Industry

Simple Bisthiocarbonohydrazones as Sensitive, Selective, Colorimetric, and Switch‐On Fluorescent Chemosensors for Fluoride Anions

Bis-thiocarbono-hydrazones are found to be a class of sensitive, selective, ratiometric, and colorimetric chemosensors for anions such as fluoride (F(-)) or acetate (Ac(-)). The sensitivities, or the binding constants of the sensors with anions, were found to be strongly dependent on the substituents appended on the pi-conjugation framework, the delocalization bridge CH==N, the aromatic moiety, and the hetero atom in the C==X group (X=O, S) of the sensors. Single-crystal structures and (1)H NMR titration analysis shows that the --CH==N-- moiety is a hydrogen-bond donor, and it is proposed that an additional CHF hydrogen bond is formed for the sensors in the presence F(-). A sensor bearing anthracenyl groups is demonstrated as a switch-on fluorescent chemosensor for F(-) and Ac(-). The recognition of F(-) in acetonitrile (MeCN) by a sensor with nitrophenyl substituents is tolerant to MeOH (MeCN/MeOH=10:1, v/v) and water (MeCN/H(2)O=30:1, v/v); at these solvent ratios the absorption intensity of the sensor-F(-) complex solution at maximal absorption wavelength was attenuated to half of the original value in pure MeCN.

Effect of substituents on diarylmethanes for antitubercular activity

Aminoalkyl derivatives of diarylmethanes were prepared using Grignard, Friedel–Crafts arylation and aminohydrochloride chain formation reactions. These series of compounds were evaluated against Mycobacterium tuberculosis H 37R v and showed the activity in the range of 6.25–25 μg/mL. Effect of heteroaryl, anthracenyl and phenanthrene groups on diarylmethane pharmacophores for antitubercular activity is described.

Syntheses and Photophysical Studies of Cyclodextrin Derivatives with Two Proximate Anthracenyl Groups

A series of permethylated cyclodextrin derivatives, cyclodextrin dimers doubly bridged with two anthracene moieties (An2CD2) and singly bridged with one (AnCD2) and the monomer bearing two anthracene moieties (An2CD), were newly synthesized. For An2CD2, the two isomeric forms are also identified. All compounds are soluble in both aqueous and various organic solvents. The bisanthracene systems, An2CD2 and An2CD, show the thermal equilibrium in an aqueous solution between the intramolecularly interacting (closed) and less-interacting (open) states of the anthracene moieties, which results in the temperature-dependent absorption changes. These systems also show the characteristic excimer emission that is enhanced in water and weakened in organic solvents. The excitation spectra for the monomer and excimer fluorescence are found to be quite different from each other and similar to the absorption spectra of the open and the closed forms, respectively. The observed unique parallelism between excitation and absorption spectra for the present excimer systems indicates the dual ground state-dual excitation scheme where the excitation state formed from the closed ground state mainly gives excimer. The fluorescence lifetime analyses reveal that the rates of the conversion from the excited state of the open form to that of the closed one (6.0 x 10(6) s(-1) for An2CD2-2) are largely retarded compared with that of the ethyleneoxy linked bisanthracene system (8.8 x 10(7) s(-1)).

Probing Shapes of Bichromophoric Metal−Organic Complexes Using Ion Mobility Mass Spectrometry

Ion mobility mass spectrometry (IM-MS) was used to probe the structures of several metal complexes carrying pendant chromophores. The three complexes investigated were the copper(II) complex Cu(DAC)2+ (DAC = 1,8-bis(9-methylanthracyl)cyclam, cyclam = 1,4,8,11-tetraazacyclotetradecane), the N-nitrosylated ligand DAC-NO, and the Roussin's red salt ester (mu-S,mu-S')-protoporphyrin-IX-bis(2-thioethyl ester)tetranitrosyldiiron (PPIX-RSE). From the IM-MS data coupled with theoretical calculations, it was found that [Cu(II)(DAC - H)]+ exists as a single conformer, with one anthracenyl group above the cyclam and the other below, similar to the crystal structure of Cu(II)(DAC)2+. The metal-free N-nitrosylated ligand (DAC-NO + H)+ has two conformations: one family of structures has one anthracenyl group above the cyclam and one below, while the other has both anthracenyl groups on the same side of the cyclam. These observations are consistent with 1H NMR data for the neutral DAC-NO complex that indicate the presence of two geometric isomers in solution. The third species, PPIX-RSE, has a porphyrin chromophore covalently linked to an Fe2S2(NO)4 cluster for use as a precursor for the photochemical delivery of nitric oxide in single- and two-photon excitation processes. Ion mobility indicates the presence of two (PPIX-RSE + H)+ conformations, consistent with the previous interpretation of the bimodal fluorescence lifetime decay seen for PPIX-RSE. DFT structures, in good agreement with the IM-MS cross sections, indicate two "bent" conformations with the planes of the porphyrin and Fe2S2 rings at different angles with respect to each other.

Polyaza and azaoxa macrocyclic receptors functionalised with fluorescent subunits; Hg2+ selective signalling

A polyazacycloalkane containing naphthyl groups, 1,4,8,11-tetrakis(naphthylmethyl)-1,4,8,11-tetraazacyclotetradecane (L1), and the azaoxa cycloalkane receptors containing anthracenyl groups, 7,13-bis(anthracenylmethyl)-1,4,10-trioxa-7,13-diazacyclopentadecane (L2) and 10-anthracenylmethyl-1,4,7-trioxa-10-azacyclododecane (L3), have been synthesized and their activity as fluorescent chemosensors studied towards the metal cations Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+ in THF–water (70∶30 v/v, 0.1 mol dm−3 tetrabutylammonium perchlorate, 25 °C) for L1 and 1,4-dioxane–water (70∶30 v/v, 0.1 mol dm−3 potassium nitrate, 25 °C) for L2 and L3. The crystal structure of the complex [Cd(L1)(Cl)][PF6] has been determined by X-ray single crystal procedures. The co-ordination geometry about the cadmium atom is near square pyramidal with the ligand showing a conformation with the four naphthylmethyl groups pointing above the N4 plane. Potentiometric experiments in THF–water for L1 in the presence of Cu2+, Hg2+ and Pb2+ and in 1,4-dioxane–water for L2 in the presence of Cu2+, Zn2+, Cd2+, Hg2+, Pb2+, and L3 with Cd2+ and Pb2+ have also been carried out. All metals form stable complexes with L1, L2 and L3 with stability constants for the formation of the [M(L1)]2+, [M(L2)]2+ and [M(L3)]2+ species in the sequence Pb2+ < Hg2+ < Cu2+; Zn2+ < Cd2+ < Pb2+ < Cu2+ ≪ Hg2+ and Cd2+ < Pb2+, respectively. The fluorescent behaviour of L1, L2 and L3 in the presence of the Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+ has been studied as a function of the pH: Cu2+ and Hg2+ selectively quench the fluorescence emission intensity of L1 at neutral and acid pH. The emission intensity of L2 is selectively enhanced in the presence of Hg2+ at basic pH. In contrast, the fluorescence intensity of the free receptor L3 at a certain pH is not modified upon addition of any metal ion. The emission sensing behaviour of L1, L2 and L3 towards metal ions is compared with the electrochemical sensing ability of analogous ferrocene-functionalised ligands.

Metal-centred versus ligand-centred luminescence quenching of a macrocyclic copper(II) complex †

The new macrocyclic ligand trans-6-(9-anthracenylmethylamino)-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecan-13-amine has been synthesized and characterised as its copper(II) complex and the crystal structure of this complex has been determined. Fluorescence of the anthracenyl group of the macrocycle is quenched in its free base form and when complexed with CuII. Fluorescence returns when Lewis acids such as H+ and ZnII are added to solutions of the ligand, indicating that photoinduced electron transfer from the amine lone pairs is responsible for fluorescence quenching in the free base form. By contrast, fluorescence of the complex is quenched by intramolecular electronic energy transfer.

Complexes of gold(I) and platinum(II) with polyaromatic phosphine ligands

Gold and platinum(II) complexes of the phosphine ligands PAr n Ph 3− n (Ar=naphthyl, anthracenyl, ferrocenyl and other polyaromatic groups) have been synthesised. The electron donating abilities of naphthyl and anthracenyl phosphine ligands has been explored using gas phase photoelectron spectral data on the parent phosphines and their relative complexing ability to platinum precursor molecules has been assessed by means of synthetic studies and NMR experiments. Their steric parameters have been estimated by the Tolman cone angle methodology using X-ray crystallographic data. The molecular structures of the gold complexes [AuCl(PAn 2Ph)]·CHCl 3 and [Au(PFc 2Ph) 2]·CHCl 3 have been determined.

A new tetraoxa-tetraaza macrobicyclic anthracenyl luminescent receptor: control of the receptor-substrate stoichiometry

The luminescent receptor 1 incorporating anthracenyl groups as luminophores and a tetraoxa-tetraaza macrobicyclic receptor as the binding subunit has been synthesized and its interactions with CaII, investigated by fluorescence measurements, are reported. The receptor-substrate 1-Ca system is an example of multistability at the molecular level, triggered by a reversible modification of the receptor ability and evidenced by luminescence.

Light-switched metal-tunneling across a π-basic tube of 1,3-alternate-calix[4]arenes

Three 1,3-alternate-calix[4]arenes ( 1 ∼ 3 ) bearing two anthracenyl groups at one side and two propoxyl or ethoxyethoxyl groups at the other side were synthesized. The aim of this molecular design is to reversibly change the metal-binding ability of the anthracene-linked side through their photoinduced cycloaddition and reverse thermal decomposition. Since certain metal cations tend to pass from one side to the other side across a π-basic calix[4]arene tube, one can expect that a light-triggered metal tunneling for this molecule. In compounds 1 and 2 the rate of the metal tunneling was faster than the 1H NMR time-scale and the distribution of metal cations between two sides could not be determined. In a 3·Ag + complex the coalescence temperature appeared at −20°C and Ag + is bound to the ethoxyethoxyl side more than to the anthracenyl side in the dark. After photoirradiation Ag + was exclusively bound to the photocycloaddition side. These results support the view that compound 3 behaves like a mechanochemical “syringe”, the action of which is controllable by light.

Concerted supramolecular motifs: inverted sextuple aryl embraces in crystalline tris(9-anthracenyl)phosphine

Crystalline tris(9-anthracenyl)phosphine 1 contains an unusual supramolecular motif, an inverted sextuple aryl embrace (ISAE) of a pair of phosphines. This embrace, which is maintained by six intermolecular edge-to-face interactions between anthracenyl groups, differs from the normal sextuple phenyl embraces (SPE) of Ph 3P in that the phosphines are inverted relative to each other. The PC vectors are directed away from the interaction zone in the ISAE, rather than into the interaction zone as in the SPE. The ISAE has 3 symmetry. The net attractive energy of this concerted supramolecular motif is calculated to be 165 kJ mol −1 for the ISAE pair. Each molecule of 1 is also involved in three quadruple anthracenyl embraces with three other neighbouring molecules, in geometry comparable with the parallel quadruple phenyl embraces of Ph 3P and Ph 4P +.

Electroluminescent devices based on modified polystyrene II. Pendant anthracenyl groups as light emitters

A new light emitting polymer with pendant anthracene based units attached to a polystyrene backbone has been obtained, namely poly(styrene- co-anthracenyl-9-methoxystyrene). It was synthesized through a Williamson condensation of poly(styrene- co-acetoxystyrene) and 9-chloromethylanthracene. The copolymer contained one chromophore for each two styrene units, and showed an emission spectral maximum entered at 590 nm.

Magnetic Hyperfine Mössbauer Spectra of Ferrocenyaldimines‐FeCl3 Adducts

AbstractFerrocenylaldimines (Fc‐CH=N‐R) were prepared by condensation of Schiff base of formylferrocene with polyacenylamines RNH2; R = naphthyl, anthracenyl and pyrenyl groups. This step was followed by oxidation with FeCl3 to give [Fc‐CH=NR]‐FeCl3 adducts. The electronic state of iron in these adducts was investigated by means of 57Fe Mössbauer spectra except for [Fc‐CH=N‐Pyr]‐FeCl3 showed that only a doublet was observed at ambient temperature. As the temperature was decreased below 200 K, additional magnetic hyperfine splitting was observed characteristic of ferric oxide.

Phosphorus derivatives of anthracene and their dimers

AbstractThe syntheses of the (9‐anthracenyl)phosphanes 2 to 7 and of the metal carbonyl complexes 8 and 9 are described. Both 1 and 4 undergo [4 + 4] cycloaddition when irradiated, forming the dimers 10 and 11. Only one of the six possible rotamers for 10 is formed. For 11 one additional rotational isomer is observed. The relationship between the [4 + 4] dimerization and steric effects of the PR2 group is discussed. The compounds 6, 8 and 11 were characterized by X‐ray diffraction. The structure of 6 was rendered imprecise by the presence of disordered toluene, but the influence of the bulky anthracenyl groups was clear, with wide CPC angles of 110.4°. The molecule displays imposed threefold symmetry. The two independent molecules of complex 8, which crystallizes as a dichloromethane hemisolvate, are closely similar to each other; the WP bond lengths are 254.3 and 253.4 pm. The WC bonds trans to phosphorus are 4 pm shorter than those cis. The phosphane dimer 11 crystallizes with imposed centrosymmetry. The H atom positions, which could be tentatively identified from difference syntheses, indicate a different rotamer than was formed for the analogous fluorophosphane dimer 10.

Mössbauer Spectroscopic Studies of Ferrocenylaldimines and their TCNQ Complexes

AbstractA series of ferrocenylaldimines (Fc‐CH=N‐R) has been prepared by Schiff base condensation of formylferrocene with polyacenylamines RNH2 where R = naphthyl, 5,6,7,8‐tetrahydronaphthyl, anthracenyl, and pyrenyl groups. This step was followed by oxidation with TCNQ to give [Fc‐CH = N‐R][TCNQ]2 salts. The electronic state of iron in these compounds was investigated by means of57Fe Mössbauer spectroscopy.

ChemInform Abstract: Novel Insight into the Photochemical cis‐trans Isomerization of Olefins

Contrary to the hitherto accepted concept that every olefins undergo mutual isomerization between their cis-and trans-isomers, olefins substituted by anthracenyl and other aromatic polycyclic groups undergo only one-way isomerization from their cis-to trans-isomers, and the reverse isomerization from their trans-tocis-isomers never occurs. The mechanism for the one-way isomerization and the features to distinguish one-way or two-way isomerization is discussed to get whole view of the isomerization of olefins.

二重結合の光異性化の新展開

Contrary to the hitherto accepted concept that every olefins undergo mutual isomerization between their cis-and trans-isomers, olefins substituted by anthracenyl and other aromatic polycyclic groups undergo only one-way isomerization from their cis-to trans-isomers, and the reverse isomerization from their trans-tocis-isomers never occurs. The mechanism for the one-way isomerization and the features to distinguish one-way or two-way isomerization is discussed to get whole view of the isomerization of olefins.